Built-up, plate type heat exchanger having spiral flow



May 4 A. HOCK, SR., ET AL BUILT-UP, PLATE TYPE HEAT EXCHANGER HAVINGSPIRAL FLOW 5 Sheets-Sheet 1 Filed Aug. 4, 1950 y N e fiMwL @CQ m MLBnventors. '4 AWN l 0CM5f.

" Max LEn A,

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y 4, 4 A. HOCK, sR., ET AL BUILT-UP, PLATE TYPE HEAT EXCHANGER HAVINGSPIRAL FLOW 5 Sheets-Sheet 2 Filed Aug. 4, 1950 Zia, X

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M y 1954 A. HOCK, SR, ET AL 2,677,531

BUILT-UP, PLATE TYPE HEAT EXCHANGER HAVING SPIRAL FLOW Filed Aug. 4,1950 5 Sheets-Sheet 5 May 4, 1954 A, HOCK, SR, ET L 2,677,531

BUILT-UP, PLATE TYPE HEAT EXCHANGER HAVING SPIRAL FLOW Filed Aug. 4,1950 a Q 2 M 5 Sheets-Sheet 4 attornegs.

ZSnnemors.

y 4, 1954 A. HOCK, SR, ET AL BUILT-UP, PLATE TYPE HEAT EXCHANGER HAVINGSPIRAL FLOW 5 Sheets-Sheet 5 Filed Aug. 4, 1950 ukes.

NW Mm Zhmentors. r41-V/N Hocx, .53, M41 LEI/4,

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Patented May 4, 1954 UNITED OFFIQTE BUILT-UP, PLATE TYPE HEAT EXCHANGERHAVENG SPIRAL FLOW' Alvin Hock, Sin, Hamilton, Ohio, and Max Leva,Pittsburgh, Pa; said Love. assignor to said Hock, Sr.

8 Claims. l

Our invention relates to improvements in builtup, plate type heatexchangers.

A principal object or" our invention is to pro vide a heat exchangerparticularly adapted for the heating or cooling of one liguid by anotherwhich is extremely efficient in operation.

Another object of our invention is to provide a built-up, plate typeheat exchanger which can be quickly and easily taken apart andassernbled as desired.

A further object of our invention is to provide a heat exchanger whichcan be cleaned with a minimum amount of effort and a minimum loss oftime.

Still another object of our invention is to to provide a heat exchangermade up of a plurality of heat exchange plates and spacer platesseparated by gaskets arranged in novel manner and carried by certain ofthe plates.

An important object of our invention is to provide a path or" flow foreach or the liquids passed through the heat exchanger that insures amaximum amount of heat transfer.

A further object of our invention is to provide a heat transfer platewhich, when positioned between two flat plates, forms two paths of flow,each path forming a spiral, one on either side or said heat transferplate.

Another object oi our invention is to provide a spiral channel having aparticular configuration when viewed in cross section arranged so as toprovide maximum heat transfer, minimum back pressure and a path of fiowunobstructed by air bubbles and the like.

ether objects and advantages of our :1ven tion wii become apparent tothose skilled i: the art during the course of the following descriptionand from reference to the accompanying drawings in which like numeralsare employed to designate like parts throughout the same and in which:

Figure 1 is sioe elevation of one form of our invention wherein aplurality of plates are arranged in two sections and employed withchange-over located between the sections,

Figure 2 is a sectional view taken on the line 2 of Figure 3.,

Figure 3 is a sectional view taken on the line 3-3 of Figure 1,

Figure 4 is an exploded view of a plurality of plates diagrammaticallydisclosing the flow of the liquids through the heat exchan er,

Figure 5 is an enlarged front elevation of a heat transfer plateemployed with our heat exchanger,

Figure 6 is a sectional view taken on the line fi-6 of Figure 5,

Figure 7 is an enlarged sectional View taken on the line Z -T of Figure5,

Figure 8 is an enlarged sectional view taken on the line 88 of Figure 5,

Figure 9 is an enlarged sectional view taken on the line 99 of Figure 5,

Figure :10 is an enlarged front elevation of a spacer plate employed inour heat exchanger,

Figure 11 is a sectional view taken on the line |l--li of Figure 10,

Figure 12 is an enlarged sectional view taken the line i2l2 of Figure10,

Figure 13 is an enlarged sectional view taken on the line l3|3 of Figure10,

Figure 14 is an enlarged sectional view taken on the line I i-l4 ofFigure 10,

Figure 15 is a section taken through one of the gaskets employed in ourheat exchanger,

Figure 16 is a section taken through a heat exchanger built according toour invention, the section being taken on a line corresponding to theline lfi-i'5 shown in Figure 5,

Figure 17 is a side elevation of a heat exchanger built according to ourinvention and made up of only one section rather than the two shown inFigure 1,

Figure 18 is a sectional view taken on the line i8-lfi of Figure 1'7,

Figure 19 is an exploded view of a plurality of the plates forming ourheat exchanger and diagrammatically disclosing the paths of flow of thevarious liquids through the heat exchanger,

Figure 20 diagrammatically discloses the how channel relationship of thefiuid from which the heat is being taken to the fluid which is absorbingthe heat,

Figure 21 is a view similar to that of Figure 20 but showing a reversedposition of the fluids, and

Figure 22 is a view similar to that of Figure 20 but showing a reversedshape of the flow channel.

General arrangement and princ ple of operation The type of heatexchanger to which our invention relates is that wherein a heat transferplate having troughs formed therein is maintained between a pair of fiatplates, there being a plurality of heat transfer plates arranged in thismanner. These plates are formed with ports and provided with gaskets andthe troughs of the heat transfer plate arranged in a spiral, so that aliquid from which it is desired to remove heat may travel through thespiral trough located on one side of the heat transfer plate and so thata fluid which is to take up the heat from the first fluid may travel inthe spiral trou located on the other side of the transfer plate and inthe opposite direction. To this end one of the fluids enters the spiraltrough at the center of the heat transfer plate and makes its way to theperimeter of said plate while simultaneously with this the other fluidenters the spiral trough on the opposite side of the plate and at theperimeter thereof, this fluid then flowing in a spiral to near thecenter of the transfer plate. It is to be understood that the heatexchanger as a whole comprises a stack of plates arranged in this mannerand that the fluid which is introduced near the perimeter of the heattransfer plates passes through the various spiral troughs substantiallysimultaneously and that the fluid which is introduced near the center ofthe heat transfer plates passes through its spiral troughs substantiallysimultaneously. That is to say, the

passage of the liquids is not serpentine or tortuous in the sense ofpassing from one spiral plate and then into the next, rather, equalportions of one type of fluid flow in the same direction in the spiralpassageways provided on one side of the heat transfer plates, eachportion traveling through its respective spiral substantiallysimultaneously with each of the other portions, and equal portions ofthe other type of fluid flow in the passageways located on the otherside of the heat transfer plates, and in the opposite direction to theflow of the first portions, each of these last portions also flowingthrough its respective spiral substantially simultaneously with theother of said portions.

In a heat exchanger of this type the amount of heat taken from one fluidand absorbed by the other is determined, aside from special features ofconstruction that will be explained later, by the length of the spiralpassageways. In any one section, that is, in any one group of platesarranged as generally described above, the number of heat transferplates determines only the quantity of fluid that can be handled in agiven time; the actual lowering or raising of the temperature of thefluid being treated is, assuming other factors to be constant,determined by the length of the spiral. If it is not feasible toconstruct a spiral of sufflcient length to effect the temperature changedesired, the liquid can be passed through one stack of plates in themanner described and then collected and passed through a second stack ofplates, this having the effect of lengthening the spiral path of travel.An arrangement of this type is shown in Figure 1.

In Figure l we have shown a heat exchanger which comprises the legs 30and SI, the lateral frame members 32 (only one of which is shown) uponwhich the various plates are hung, and two groups or sections of plates,one generally indicated at 33 and the other at 34. These sections areseparated by change-over means generally indicated at 35. The heatexchanger includes a pair of end members 36 and 37. Also, in connectionwith the end member 31 we have provided screw-down mechanism comprisingthe spider 38, bolts 39, springs 4e, screw 4| and crank 42. Thisscrew-down mechanism is of conventional design and so arranged that thestacks. of plates comprising the sections 33 and 34 can be forcedtogether with any desired amount of pressure. The

springs 45 add resiliency necessary to accommodate expansion andcontraction of the plates caused by the temperature of the variousfluids flowing therethrough.

Although the heat exchanger developed by us is particularly adapted andsuited for use in breweries wherein it is desired to cool the wort bycold water, it is to be understood that we do not intend to be limitedby the specific fluids used although we shall hereinafter refer to theliquids as wort and water for the sake of convenience and cleardescription. Thus the heat exchanger of Figures 1, 2 and 3 is shownprovided with a conduit 43 for the entrance of wort, a conduit 44 forthe exit of water, an exit conduit 45 for wort and an entrance conduit46 for Water. The conduits 43 and 44 lead into the member 35; theconduits 45 and 46 lead into the member 31. Each of the plate sections33 and 34 comprises a plurality of heat transfer plates 47 alternatelyarranged with a plurality of spacer plates 48 (see Figure 4). The endspacer plates may comprise the inner faces 35a and 31a of the endmembers 36 and 3?.

As is best seen in Figures 5 and 6, and as will be described in greaterdetail shortly, each of the heat transfer plates 41 comprises a metalplate into which there has been pressed or otherwise formed a spiralpassageway on one side of the plate and a corresponding spiralpassageway on the other side thereof. Each of the spacer plates 48, asis best seen in Figures 10 and 11 and as will be described in greaterdetail shortly, comprises a metal plate which is substantially flat.When a plate 48 is pressed against a plate 41, a spiral trough is formedin such manner that liquid flowing between the plates must flow throughthe spiral trough.

The general principle of operation of a heat exchanger of this type isdiagrammatically illustrated in Figure 4. In this figure the water isdepicted as flowing on the backside of the heat transfer plates 4'! and,therefore, the arrows indicating its path of travel on the plates areshown in broken lines. The wort is here shown as traveling on the frontsides of the heat transfer plates 41 and therefore the arrows depictingsuch travel are shown in full lines on these plates. Each of the plates41 and 48 (with the xception of the end plates) is formed with fourports, one each at the upper right and left hand portions of the plateas viewedin Figure 4 and a pair located substantially centrally of theplate. These ports are indicated at 49, 50, 5! and 52. Some of theseports are diagrammatically shown as having portions broken away as at49a, 50a, 5m and 52a. Wherever a port is shown as so broken, it meansthat the fluid flowing through that port is also free to flow on thatside of the plate on which the break in the port is indicated.

A portion of a quantity of water that enters the heat exchanger throughthe conduit 46 flows through the port 49 and into the spiral passagelocated on the backside of the first plate 41 (viewed in Figure 4 fromright to left) as is indicated by the break 49a shown on the front sideof the spacer plate 48. Some of the Water introduced into the exchangerthrough the conduit 46, however, passes on through the ports 49 to thesecond heat transfer plate 4"! where, as indicated by the break 49a onthe port 49 shown on the back end plate 36a, this water also travels ina spiral trough on the backside of this second heat transfer plate 41.Because the water will be introduced intothe conduit 45 in greatquantity, the water flowing in the spiral trough on the first plate 47and that flowing in the spiral trough on the backside of the secondplate 41 will be traveling through their respective channels subma numstantially simultaneouslywith one another. After the water flows throughthe spiral channels in the manner described it comes to the port 52located near the perimeter of each plate. This water then flows out ofthe heat exchanger through the conduit 34. Since the ports '52 locatedon the front side of the heat transfer plates are not broken, the watercannot pass into channels located on the front sides of the heattransfer plates and therefore it will discharge through the conduit 44as just explained.

A quantity of hot wort is introduced into the heat exchanger through theconduit 43. A portionof this wort will, as indicated by the break 51a inthe port 51 of each of the heattransfer plates 41, enter the spiralchannel located on the front side of one of the heat transfer plates4''! and simultaneously therewith another portion of the wort will enterin the. channel located on the front side of another of these plates41'. When the wort has passed through its: respective channels it isdischarged from the exchanger by means of the ports 55 which communicatewith theexit conduit 45. As indicated by the full line ports shown onthe spacer plate 48. and back; end

plate 35a the wort cannot getinto theispiral channel located on thebackside of the heat transfer plates 47.

From the foregoing description it should be clear that the generalprinciple of operation of our heat exchanger involves conducting aquantity of hot wort through a spiral channel located one one side of aheat transfer plate, the spiral commencing near the perimeter of theplate and ending near the center thereof, and: at the same time passinga quantity of cold water into a spiral passage located on the other sideof said heat transfer plate, the latter spiral passage beginning nearthe center of the plate and ending near its perimeter. This arrangementisrepeated for a plurality of plates, the various heat transfer platesbeing separated by spacer plates which serve to close the front side ofthe channels and insure that the liquids follow the spiral paths ratherthan flow over the edges separating one convolution from another.

In Figure 16 we have shown a section taken. through a unit generallycorresponding to that shown in Figure 1. This unit comprises a firstsection 33 of plates 41 and 48 alternately arranged and maintainedbetween a portion 35a of the change-over means 35 and the face 35a ofthe end member 35. Also included is a second section 34 comprising aplurality of plates 4] and 43 alternately arranged and maintainedbetween v the portion 35b of the change-over means 35 and and the face330: of the end member 31. It will be understood that the members 35 and31 are clamped together by the screw down mechanism shown in Figure l orby other suitable arrange ments such as, for example, a hydraulic systemconventional in arts of this general class.

The various plates are provided with gaskets which serve to insure theproper flow of the wort and water. Hot Wort which is introduced throughthe conduit 43 will be directed on the upper side of each of the heattransfer plates 41 (upper side as viewed in Figure 16) and will make itsway to the center of the heate'xchanger via the spiral troughs formed bythe heat transfer plate ll as closed by the spacer plate d8. In Figure16 the relative position of the Wort is indicated by solid arrows, thatof the Water by broken arrows. The wort which travels the plurality ofspiral paths substantially simultaneexits via the conduit 45.

ously to the port .near the center of' the exchanger then -passesthroughthe opening 35b into the change-over box 35. This change-over box 35comprises a portion 35a having a central rib 53 and a portion 351) witha similar rib 54. Gaskets 55 and 55- serve to maintain the portions 35aand 35b in liquid tight relation to one another.

The batch of. wort which is passed through the opening; 350 into thechange-over means 35 is then directed through the passage 35d whichleadsinto the second section 34. This wort again travels through spiralpaths on the upper side of the heat transfer plates to a location nearthe :centerof the heat exchanger from which it then In this manner hotbeer introduced at 43 is subjected to a first cooling action and then,by means of the second section- 34, is subjected to a further coolingafter which it is discharged from the heat exchanger at 45.

The cold water or cooling medium used is introduced at '45. This coldfluid then passes through the spiral troughs located on the underside ofeach of the heat transfer plates 41 to the outer edges of the platesfrom which location it is then directed into the change-over means 35via the passage 51. This fluid then passes-through the opening 58 andagain takes aspire-lcourse on the underside of the plates 41 fromnearthe center of the exchanger to the outer edges thereof. This fluidthen exits thoughthe conduit M. It should be noted that bythisarrangement we have insured that the coldest. water is in heat exchangerelation with the coolest wort and that the warmest water is inv heatexchange relation with the hottest wort. Bythis provision we insure thatthe heat always passes from-the wort to the Water and not from the waterto the wort at any stage. Thus the hottest. wort which is introduced at43 is in its first stage (section 33) somewhat cooled by the water whichwas introduced at 58. This water, while somewhat warm from its passagethrough the section 34, .is still much cooler than the hot wort and ittherefore serves to further cool the wort. The somewhat cool Wort fromsection 33 then passes into section 34 via the passageway 3501. Thissomewhat cool wort contacts the very cold water introduced at and againthe result is that the wort is further cooled while the water becomessomewhat warmer.

The heat transfer plate The heat transfer plate 4'! utilized in our heatexchanger is shown in detail in Figures 5 through 9-. As shown in Figure5 the plate 47 is of a shape which nicely lends itself to the provisionof: a spiral passage and the pair of ports 5| and 52. It should be notedthat the particular side of the heat transfer plate shown in Figure 5 isthe wort side,. that is, it is the side of the plate on which the fluidfrom which it is desired to remove heat travels. The corresponding sideof :this, plate in Figures 6 through 9 is the upper side as viewed inthose figures. As will be pointed out shortly it is extremely importantthat the fluid from which. it is desired to remove heat passes throughthe spiral troughs located on the upper side of the heat transfer platell and not onithe'l'ower side thereof.

The-spiraltroughs on the plate 41 may be described .as follows. A pairof oppositely disposed spiral grooves 58 and 60' are pressed orotherwisesuitablyaformed in=the plate 41. Each groove 59 and-6.0 isjoined by a wall 61 which, in order to provide a maximum amount of heattransfer surface, is preferably slanted. The grooves just referred toare those which lie immediately adjacent one another. Formation of thegrooves 59 and '50 results in a pair of oppositely disposed ridges 62and 63 as viewed in cross section (see especially Figure 7). The spiralgrooves 59 and 60 are arranged in fairly wide convolutions such that thedistance from a given convolution of the ridge e: to the next ridge 63,reading from right to left in Figure 7, is substantially greater thanthe lateral distance between said given convolution of the ridge '52 andthe next ridge 63, reading from left to right in this figure. Thegrooves 59 and 60 reading from right to left, are joined by a portion 5which, while slanted, is, again to insure greater heat transfer surface,staggered as at Ma. Thus the spiral trough on the upper side of the heattransfer plate 4! is defined by the pair of ridges 62 which are joinedby the staggered slanted portion 84 and one of the slanted portions 66.The trough on the lower side of the plate ll! which corresponds to thespiral trough just described is defined by the ridges which are joinedby the same slanted staggered portions 64 one of the other slantedportions iii.

In brief then, the heat transfer plate may be described as having aspiral ridge 62 on one side thereof, the plate remaining betweenconvolutions of this ridge constituting the major portion of the bottomof a trough having the ridge for its sides, and as having another spiralridge 63 located on the other side thereof and slightly offset from theridge 62. remaining between convolutions of this ridge 63 is the same asthat remaining between convolutions of the ridge 02. The trough on thisother side of the heat transfer plate thus has the same major bottomportion as that of the -rst trough described but has sides correspondingto the convolutions of the ridge-63. The minor bottom portion of thetrough between convolutions of the ridge 62 consists of a slant wall Blthe minor bottom portion of the trough between convolutions of the ridge63 consists of that slant wall 6! next adjacent the slant wall 6| firstconsidered.

We have mentioned that with a heat transfer plate constructed in themanner just described it is extremely important that the fluid from fromwhich the heat is to be removed flows through the spiral troughs locatedon the upper side of the plate it, that is, through the trough definedby the convolutions of the ridge 62. That this is true is clearly shownin Figures 20, 21 and 22. In Figure the hot wort is indicated asbeginning its travel in the spiral trough located near the perimeter ofthe plate 4'! and working its way towards the center of the plate. Inthis connection it should be understood that Figures 20, 21 and 22 showportions of the plate 41 as found on the right side of Figure 16. Thewater is traveling in the opposite direction on the opposite side of theplate, that is, it is traveling in the trough formed by the convolutionsof the spiral ridge 63. For the sake of illustration only we haveindicated that the hot wort is cooled as it passes successively from theoutermost portions of the trough into the innermost portions. The changein temperature of this wort from convolution to convolution is indicatedas 190 F., 170 F., and 150 F. Thesefigures are by way of illustrationonly. Similarly, the water flowing in the spiral trough defined by Theplate 54 convolutions of the ridge 63 is illustrated as becoming warmeras indicated by the figures F., F., and F. It will be observed that atrough defined in cross-section by a pair of convolutions of the ridgeE2 varies from a shallow portion at the right side thereof to a deeperportion at the left side, reading in the general direction of flow ofthe wort from the outside towards the center, or as viewed from right toleft in Figure 20. As will now be shown this relationship is alsoimportant.

From the temperatures arbitrarily chosen for the purpose of illustrationand indicated in the respective troughs shown in Figure 20, it will beobserved that the wort in the convolution desi nated F., is being cooledthrough the heat transfer portions fi l-64a by water which is at 130 F.,and, through the portion 6|, by water which is 110 F. If these samefigures are used and the same direction of flow used, but the water andwort reversed as to the sides of the plate 41 on which they are located,an entirely different result is obtained. This is shown in Figure 21. Inthis figure it will be observed that wort at 170 F., is cooled by waterat 130 through the heat transfer portion til-454a, and also by water at150 through the heat transfer portion 61. Thus it will be observed thatwherein the wort of Figure 20 is cooled by water 130 and 110, this samewort when located on the opposite side of the plate and cooled by waterarranged in the same sequence, is cooled by water at 130 and 150. It isthus obvious that the arrangement of Figure 20 is much more efficient.For this reason it is a distinct feature of our invention that the wort,or the fiuid from which it is desired to remove heat, is located on theparticular side of the plate 41 as just described.

In Figure 22 the Wort is shown at the same temperatures and moving inthe same temperatures and moving in the same direction and located onthe same side of plate 41 as is the case in Figure 20. The water ofFigure 22 is also arranged in the same way as that of Figure 20. InFigure 22 there has, however, been one important change. This change hasbeen a reversal of the ridges 62 and 63, that is, whereas in Figure 20the ridge 62 extends upwardly from the plate 41, in Figure 22 this ridge62 extends downwardly thereof. This reversal results in the troughlocated on the upperside of the plate 41 varying, in the direction offlow of the wort from the outside towards the center, from a deepportion to a shallow portion, which is opposite from that arrangementspecified in Figure 20. This reversal results in the same inefiicientoperation inherent in the arrangement described in connection withFigure 21. Thus the 170 wort is cooled by water at 130 and by water at150 whereas in Figure 20 the 170 wort was cooled by water at 130 and110. Figures 21 and 22, of course, illustrate substantially the samepoint. Whereas in Figure 21 the water and wort are shown as reversed inposition from that of Figure 20, in Figure 22 the plate 41 has simplybeen turned upside down and the water and wort maintained in the generalposition of Figure 20. In either event, Figures 21 and 22 show that thearrangement of Figure 20 is the most eflicient and it is sucharrangement that applicants particularly stress.

. Ln Figures 5 through 9 another feature of our invention is shown. Asmost clearly shown in Figures 8 and 9 the heat transfer plate 41 isprovided with a groove 65 which generally corresponds with the perimeterof the plate 41. In this groove 65 there is firmly secured a gasket 66of suitable material. This gasket is the only gasket which is fixed tothe plate 4]. On the underside of the plate 4? and surrounding the port5| is a groove '57 adapted to receive a gasket which is secured to thespacer plate 48 as will be described more fully shortly. The purpose ofthis latter groove and gasket is to insure that water on the undersideof plate fill does not enter the port 5! and thus mix with the wort onthe upperside of plate 4'5. In this connection it should be rememberedthat wort is passed through the port 5|.

As shown in Figure 9 the port 52 issurrounded by a groove '63 located onthe upperside of plate 41. This groove is designed to receive a gasketwhich is fixed to a spacer plate 56. The purpose of this groove andgasket is to insure that water, which is passed through the port 52,does not enter onto the upperside of plate 41 and mix with the wortwhich is there flowing. In addition. to these grooves, the plate 4'! isprovided with a small ridge 69 which is located outwardly from thegroove 65 and which extends completely around the plate 4?. The purposeof this ridge is to provide an abutment for a gasket located on a spacerplate 48 as will be described shortly.

In similar manner it will be observed, in Figure '7, that the port isprovided with a groove '10 located on the underside of plate 41 andadapted to receive a gasket fixed in a spacer plate 48, The port 49 issurrounded by a groove ll located on the upperside of plate 4.1 and thisgroove is also adapted to receive a gasket located in a spacer plate 48.

Inorder to insure that the wort which is finally discharged from the endof the trough indicated at 12 in Figure 5 contacts the greatest possiblesurface. of the plate 41, we have provided a baffle 13 between the port50 and the discharge end 12 of the wort trough, This bafile prevents thewort from immediately passing through the port 50 and thereby leavingthe heat exchanger. With the baffle positioned as indicated, it is firstnecessary that the wort pass around it before it can reach the opening50. This arrangement insures that the wort will contact a greatersurface area about the ports 50 and 49 thereby increasing the efficiencyof the heat exchanger.

The spacer plate In Figures 10 through 14 we have shown the spacer plateutilized in our heat exchanger. This spacer plate comprises a flat plateprovided with a plurality of ports 49, 50, 5! and 52 which correspond tothe ports similarly designated and located in the heat transfer plate41. The spacer plate this also provided with a number'of grooves inwhich gaskets are located as shall now be described.

As most clearly seen in Figures 11, 13 and 14, the spacer plate 48 isprovided with a groove it which extends completely around the plate andgenerally corresponds to the perimeter thereof. In this groove 14 thereis fixed a suitable gasket 15. This groove and gasket are so designedthat when a plurality of the plates ii and 48 are stacked in alternatingfashion, the gasket l5 will abut against the underside of the plate 41and against the ridge 69 provided therein. It should be observed thatthe'gasket IE-is so located that it will bear against the plate Allthrough a line of contact which is outside of the gasket 66 carried bythe plate-41.. The importance of this will be described shortly.

onto the lower surfaces of the plate 41.

As best seen in Figure 12 the port 5c is surrounded by a flange 76having indentations 11. Corresponding to the flange 36 is a groove 18 inwhich there is fixed a suitable gasket 19. When placed on top of a heattransfer plate 41 the flange it is adapted to bear against a shoulder 8%provided in the plate 41 about the corresponding port 59. This contactof the flange 16 with the shoulder 80 insures added stability in theheat exchanger. The indentations Tl serve to permit wort located on theupperside of plate 4 to enter theportsfifi and thereby bedischarged fromthe exchanger (or carried by means of the change-over box 35 to anothersection of the exchanger). At the same time the gasket 79 is designed tofit within the groove 10 located on the heat transfer plate and in thismanner wort which is passed through the ports 56 is prevented fromflowing onto the underside of the heat transfer plate 47.

Again referring to Figure 12 it will be observed that the port 49 isprovided with a flange Bi which surrounds it on the upperside of theplate 48. This flange 8! is indented as shown at 82. A groove 83corresponds to the flange 8i and a gasket 3:3 is fixed within thisgroove. When a heat transfer plate ll is placed on top of the plate 48-.

the flange 81 bears against a corresponding shoulder 85 surrounding theport 49 and located on the transfer plate 41. :At the same time thegasket 8 -5 fits into the groove 1| located on the heat transfer plateimmediately below the spacer plate 48. "Water which flows through theports 49 flows onto the underside of the various heat transfer plates 41by reason of the indentations 32 providedin the flange 81. The contactbetween flange 8i and shoulder 85 lends stability to the heat exchanger.The gasket 84 and groove 'lll' prevent any of this water from flowingonto the upperside of the heat transfer plate 41.

The ports El and 52 are arranged in the same manner as the ports 49 and5.0. Thus in Figure 13 there is shown a flange 86, groove 8?, gasket '88and indentations 89. The flange 86 bears against a shoulder 90 providedon the plate 41 for its respective port 5|. The gasket 33 is received bythe groove 61 provided in a plate 47. Wort which flows through the ports5| is thus permitted to flow onto the upper surface of the plate i'i butis prevented by the gasket 88 from flowing As shown in Figure 14 theport 52 is provided with a flange 5|, groove '92, gasket 93 andindentations The flange 9i bears against a shoulder 95 provided on theplate 4! for the port 52 and the gasket 93 fits into the groove 88 alsoprovided on the plate 4's. By this arrangement water is permitted toflow from the underside of the 'heat transfer plate 4'! into the ports5?. from which it is led from the exchanger. This water is,

however, prevented from reaching the uppersides.

of the heat transfer plate t? by reason of the gasket 93 and itsposition in the groove 68.

In Figure 15 we haveshown a section through a gasket which we employ inconnection with the ports provided in the spacer plate 48. By way ofexample this gasket has been depicted as that used about the port 52. Itshould be observed that the gasket 93 is provided with cut away portions93c corresponding to the indentations 94. This gasket is scalloped asindicated at 95 in order to provide a tighter fit in its respectivegroove 68.

The position of the various gaskets is clearly shown Figure 16. It wasearlier emphasized that a particular feature of our invention was thefact that the main gasket carried by the spacer plate 48 was locatedoutside of the main gasket 66 carried by the heat transfer plate 41. Tothis end the spacer plate 48 is provided with a ridge 9? against whichthe gasket 66 abuts (see Figures 13 and 16). The purpose of the maingasket '55 is to hold the water within the confines of the heat transferand spacer plates. The purpose of the main gasket 66 is to maintain thewort within the confines of the heat transfer and spacer plates. Thereason for specifically locating the gasket 15 on the outside of theposition of gasket 66 is to prevent the wort from accumulating in thedead spaces that develop as indicated at 98 in Figure 16. Thisparticular arrangement of the gasket 66 and 15 not only makes the uniteasier to clean in that there is no chance of the wort becoming caughtin dead spaces and adhering to the plates therewithin but also it lendsgreater sanitation to the heat exchanger as a whole. As clearly shown inFigure 16 it is not possible for the wort to become trapped beyond theconfines of gasket 66. It should also be noted that all of the portgaskets are fixed to the spacer plate 48 and that the only gasket fixedto the heat transfer plate is the main gasket 6%. This arrangement makesour heat exchanger extremely easy to assemble, disassemble and clean.Such arrangement is a distinct feature of our invention.

One-section heat exchanger In Figures 17, 18 and 19 we have shown a heatexchanger which is generally similar to that shown in Figure l butdiffers in that we employ only one stack of spacer plates and heattransfer plates rather than the two stacks 33 and 34 used in theembodiment of Figure 1. In the embodiment of Figure 17 we are able toprovide a heat exchanger in which all of the inlet and outletconnections are located at one end of the machine. Instead of using twosections to effect the cooling or heating of the liquid as is desired,we employ the one section which in most cases will utilize larger platesin order to provide longer spiral troughs and thus obtain resultsfavorable with those obtained by the exchanger of Figure 1. On the heattransfer plates 41 the flow of the water is indicated in solid lines andthe flow of the beer in broken lines. In this connection it should bedistinctly understood that the flow of the water, of the wort and thearrangement of the channels correspond to the requirements illustratedin Figures 20 through 22 and fully explained aboveT Thus as the wortmoves from the perimeter of the plate 41 in a spiral path ending nearthe center of this plate, the channel, as viewed in cross section, mustbe such that the portion near the perimeter is shallower than that nearthe center of the plate.

Cold water which enters the exchanger through the ports is circulatesoutwardly into the ports 52 through which it is exited. To accomplishthis it will be observed that the last spacer plate or end clampingmember 31 will have no ports therethrough. Thus water which is collectedin the ports 50 can exit from the exchanger only by coming back out thefront end thereof, that is, the same end of the exchanger from which itstarted. Similarly, wort which is introduced through the ports 5| andspirally circulated to the ports 56 must also be discharged from themachine at the same end thereof. Because the quantity of waterintroduced into the exchanger :i'i receives equal portions of waterwhich are I started through their respective spiral troughssubstantially simultaneously with one another.

This is also true of the wort.

It is to be understood that modifications can be made to our inventionwithin the scope and spirit thereof and although we have shown ourinvention as embodied in certain structure we do not intend to belimited by such structure except insofar as it is specifically includedin the subjoined claims. Having thus described our invention what weclaim as new and what we desire to protect by Letters Patent is:

1. A heat exchanger for transferring heat from one fluid to a secondfluid which comprises a pair of spacer plates and a heat transfer platetherebetween, said heat transfer plate having a spiral ridge on eachside contacting the respective spacer plates, said ridges being offseton the two sides of said heat transfer plate and the adjacent ridges onopposite sides of said heat transfer plate being connected by a wall ofsubstantial slant extending between said spacer plates so that theconvolutions of each ridge constitute on the opposite sides of said heattransfer plate a spiral trough, the successive convolutions of eachridge being separated by said slant wall and a second slant wall ofgreater length than said first mentioned slant wall, said slant wallsconstituting the bottom of said spiral troughs, the

r spiral trough between successive convolutions of the ridge on one sideof said heat transfer plate extending from a shallow portion adjacent anouter convolution to a deeper portion adjacent the next convolutioninwardly of said outer convolution, the spiral trough on the other sideof said heat transfer plate having its shallow portion opposite the deepportion of the spiral trough on said one side of said heat transferplate and having its deep portion opposite the shallow portion of thespiral trough on said one side of said heat transfer plate, means forproducing a flow of said one fluid in the spiral trough on said one sideof said heat transfer plate and in a direction from the outermostconvolution to the innermost convolution, and means for producing a flowof said second fluid in the spiral trough on said other side of saidheat transfer plate and in a direction from the innermost convolution tothe outermost convolution.

2. The heat exchanger of claim 1 in which said second slant wall isstepped.

3. A spacer plate for use in heat exchangers of the type described, saidspacer plate being substantially fiat and having a pair of centrallylocated openings therein and a pair of openings located near the edge ofsaid plate, a groove on one side of said plate surrounding one openingof said pair of centrally located openings and adapted to have a gasketfixed therein, a groove on said one side of said plate surrounding oneopening of said other pair of openings and adapted to have a gasketfixed therein, and raised portions on the other side of said platesubstantially opposite each of said grooves, said raised portions havingindentations therein.

4. The spacer plate of claim 3 including a groove on said other side ofsaid plate surrounding the other opening of said pair of centrallylocated openings and adapted to have a gasket fixed therein, a groove onsaid other side of said answer plate surrounding the other opening ofsaid other pair of openings and adapted to have a gasket fixed therein,and raised portions on said one side of said plate substantiallyopposite each of said last two mentioned grooves, said raised portionshaving indentations therein.

5. A heat exchanger for transferring heat from one fluid to anotherwhich comprises a plurality of alternateiy heat transfer plates andspacer plates: each of said heat transfer plates having a fluidconducting spiral trough on each side thereof, said spiral troughs beingdirectly opposite one another, a pair of centrally located ports, a pairof ports located adjacent the edge of said heat transfer plate, thespiral trough on one side of said heat transfer plate extending from oneof said edge ports to one of said central ports and the spiral trough onthe other side of said heat transfer plate extending from the other ofsaid central ports to the other of said edge ports, a. groove on oneside of said heat transfer plate, a gasket fixed in said groove, and aridge on said heat transfer plate outwardly oifset from said groove andlocated on the other side of said heat transfer plate; each of saidspacer plates being substantially flat and having a pair of centrallylocated openings therein and a pair of openings located near the edge ofsaid spacer plate, a groove on one side of said spacer plate locatedadjacent the perimeter of said spacer plate and surrounding all of saidopenings, a gasket fixed in said groove, and a ridge inwardly offsetfrom said groove and located on the other side of said spacer plate;said heat transfer plates and said spacer plates being so arranged thatthe gasket fixed in a heat transfer plate bears against a said inwardlyoffset ridge located on a spacer plate, and the gasket fixed in a spacerplate bears against the outwardly offset ridge of a heat transfer plate,whereby when the plates are in stacked relation the gaskets fixed insaid spacer plates lie outside of the gaskets fixed in said heattransfer plates.

6. A heat exchanger for transferring heat from one fluid, to anotherwhich comprises a plurality of alternately arranged heat transfer platesand spacer plates: each of said heat transfer plates having a spiraltrough located on each side thereof, a pair of centrally located ports,a pair of ports located adjacent the edge of said heat transfer plate,the spiral trough on one side of said heat transfer plate extending fromone of said edge ports to one of said central ports and. the spiraltrough on the other side of said heat transfer plate extending from theother of said central ports to the other of said edge ports, a gasketreceiving groove on one side of said heat transfer plate surrounding oneport of said pair of centrally located ports, a gasket receiving grooveon said one side of said heat transfer plate surrounding one port of theother pair of ports, a gasket receiving groove on the other side of saidplate surrounding the other port of said pair of centrally locatedports, and a gasket receiving groove on said other side of said heattransfer plate surrounding the other port of said other pair of ports;each of said spacer plates being substantially flat and having a pair ofcentrally located openings therein and .a pair of openings located nearthe edge of said spacer plate, a groove on one side of said spacer platesurrounding one opening of said pair of centrally located openings, agasket fixed in said groove, a groove on said one side of said spacerplate surrounding one opening of the other pair of openings, at

14 gasket fixed in this last mentioned groove, a groove on the otherside of said spacer plate surrounding the other opening of said pair ofcentrally located openings, a gasket fixed in this last mentionedgroove, a groove on said other side of said spacer plate surrounding theother opening of said other pair of openings, and a gasket fixed in thislast'mentioned groove, each of the grooves in said spacer plate having araised portion on that side of said spacer plate which is oppositefromthat side in which the respective groove is located, said raisedportions having indentations; said heat transfer plates and said spacerplates being so arranged that the gasket fixed in the I groovesurrounding one of the centrally located openings willfit into thegroove surrounding one of the centrally located ports, and the gasketfixed in the groove surrounding one of the other pairs of openings willfit into the groove surrounding one of the other pair of ports, and theindented raised portion surrounding one of the centrally locatedopenings will bear against a heat transfer plate about one of thecentrally located ports on the side of said heat transfer plate oppositethat in which the gasket receiving groove for said last mentioned portis formed, and the indented raised portion surrounding one of the otherpair of openings will bear against a heat transfer plate about one ofthe other pair of ports on the side of said heat transfer plate oppositethat in which the gasket receiving groove for said last mentioned portis formed.

7 A heat exchanger for transferring heat from one fluid to a secondfluid which comprises a pair of spacer plates and a heat transfer platelocated therebetween, said heat transfer plate having a spiral troughlocated on each side thereof, said heat transfer plate having fourports, one pair of said ports communicating with the spiral trough onone side of said heat transfer plate and the other pair of said portscommunicating with the spiral trough on the other side of said heattransfer plate, one port of each pair being adjacent the innermost endof the respective spiral trough with which it communicates, and theother port of each pair being adjacent the outermost end of therespective spiral trough with which it communicates, said spacer platebeing provided with two pairs of openings, one pair of said openingsregistering with one of said pairs of ports and the other pair ofopenings registering with the other of said pairs of ports, and fourport gaskets carried by said spacer plate, each gasket surrounding asaid opening, one pair of said gaskets being positioned on one side ofsaid spacer plate and the other pair of said gaskets being positioned onthe other side of said spacer plate, each of said port gaskets beingmaintained in a groove surrounding a, said opening, said groove being soformed as to provide a raised portion on the side of said spacer plateopposite that side on which the groove is located, said raised portionhaving a plurality of indentations, whereby when said spacer plate andsaid heat transfer plate are maintained together one pair of saidgaskets abuts said heat transfer plate about one pair of said ports, andone pair of indented raised portions abuts said heat transfer plateabout the other pair of said ports.

8. A heat exchanger for transferring heat from one fluid to anotherwhich comprises a pair of spacer plates and a heat transfer platelocated therebetween, said heat transfer plate having a spiral trough oneach side thereof, means for directing said one fluid into the outerconvolu- 15 tions of the spiral trough on one side of said heat transferplate, means for directing the other fluid into the inner convolutionsof the spiral trough on the other side of said heat transfer plate,means for removing said one fluid from between said plates atthe innerend of the spiral trough on said one side of said heat transfer plate,means for removing the other fluid from between said plates at the outerend of the spiral trough located on said other side of said heattransfer plate, a first gasket surrounding the spiral trough in whichsaid one fluid flows, said first asket being located between said heattransfer plate and one of said spacer plates, and a second gasketsurrounding the spiral trough in which the other fluid flows, saidsecond gasket being located between said heat transfer plate and theother of said spacer plates, said gaskets being offset from one anotherso that said second gasket lies bel6 yond said first gasket, said firstgasket being fixed in a groove provided in said heat transfer plate, andsaid second gasket being fixed in a roove provided in a said spacerplate, and said second gasket bearing against a ridge provided on saidheat transfer plate.

References Cited in the file of this patent UNITED STATES PATENTS\Number Name Date 2,039,216 Feldmeier Apr. 28, 1936 2,217,567 Seligmanet a1 Oct. 8, 1940 2,251,066 Persson et a1 July 29, 1941 FOREIGN PATENTSNumber Country Date 396,696 Great Britain July 31, 1933 496,830 GreatBritain Dec. 7, 1938

